Carbon nanotubes (CNT), functionalized by biomolecules, are attracting much attention because of their promising biomedical applications, for instance, using as novel drug, DNA and protein transporters for therapy purposes. Non-covalent interactions widely exist in CNT-bioconjugates and play very important roles on solubility in aqueous solutions and internalization of CNT into living cells. However, such weak interactions in CNT-biosystems are far from being well understood at a molecular level. The major goal of the project is to well understand the non-covalent interactions among the CNT-bioconjugates with state-of-the-art first principles based tools such as density functional theory calculation, quantum and classical molecular dynamics simulations. The objectives of the project are: (1) to validate an appropriate density functional theory as well as an effective first principle-based protocol to describe non-covalent interactions and charge transfer between CNTs and biomolecules such as DNA bases, amino acids, polypeptides and so on; (2) to provide benchmark results at a molecular level for the nature of the non-covalent interactions between CNTs and biomolecules like DNA bases, amino acids, DNA oligonucleotides, and polypeptides; (3) to clarify a few important issues for the non-covalent interactions between CNT and DNA-protein systems via multi-scale molecular modeling and simulations, such as interaction mechanism, the major driving force, interaction dependence on the diameters and electronic structure of single-walled CNTs (SWCNTs), and interaction dependence on the composition and sequence of polypeptide and DNA oligonucleotides; (4) to well understand cellular internalization mechanisms of SWCNT-biomolecule conjugates into living cells. Development of new and efficient drug delivery system is very important to improve the therapeutic profile of drug molecules. The advancement of carbon nanotube functionalization has opened up new possibilities in this field. Theoretical investigations of the interface and interactions between biomolecules and CNT could provide understanding and description for CNT-bioconjugates at a molecular level. Such knowledge could eventually help design a new generation of drug delivery systems based on CNTs.